Introduction:
A linked list is a data structure that consists of a sequence of nodes, where each node contains a reference to the next node in the sequence. There are different types of linked lists, such as linear linked list and double linked list. Each type has its own advantages and disadvantages depending on the specific operation being performed. In this case, we are considering four different operations and determining which one is more efficiently performed by a double linked list compared to a linear linked list.

Operations:

a) Deleting nodes whose location is given:
- Both linear and double linked lists can efficiently delete nodes whose location is given.
- In both cases, the time complexity is O(n) since we need to traverse the list to find the node to be deleted.
- Therefore, this operation is not more efficiently performed by a double linked list compared to a linear linked list.

b) Searching an unsorted list for a given item:
- Searching an unsorted list requires traversing the list node by node until the desired item is found.
- In a linear linked list, we can only traverse the list in a forward direction, starting from the head node.
- However, in a double linked list, we can traverse the list both forward and backward, starting from either end.
- This extra flexibility allows us to potentially find the desired item faster in a double linked list compared to a linear linked list.
- Therefore, searching an unsorted list for a given item is more efficiently performed by a double linked list.

c) Inserting a node after the node with a given location:
- Both linear and double linked lists can efficiently insert a node after a given location.
- In both cases, the time complexity is O(n) since we need to traverse the list to find the node after which the new node is to be inserted.
- Therefore, this operation is not more efficiently performed by a double linked list compared to a linear linked list.

d) Traversing the list to process each node:
- Traversing a linked list to process each node requires visiting each node in the list one by one.
- Both linear and double linked lists can traverse the list in a forward direction, starting from the head node.
- However, in a double linked list, we can also traverse the list backward, starting from the tail node.
- This extra flexibility allows us to potentially process each node faster in a double linked list compared to a linear linked list.
- Therefore, traversing the list to process each node is more efficiently performed by a double linked list.

Conclusion:
- Among the given operations, searching an unsorted list for a given item and traversing the list to process each node are more efficiently performed by a double linked list compared to a linear linked list.
- Deleting nodes whose location is given and inserting a node after the node with a given location are not more efficiently performed by a double linked list.